Pressure-fluid-operated tool



April 2, 1929. E. H. SHAFF Y PRESSURE FLUID OPERATED TOOL Filed Feb. l, 1925 N 5 SM Q u Q am En Patented Apr. 2, 1929.

UNITED STATES PATENT OFFICE.

`Illl:'t1\`l}lSlI H. SHAFF, OF GRAND HAVEN, MICHIGAN, ASSIGNOR T0 WILLIAM H. KELLER, INC., OF GRAND HAVEN', MIGHIGAN, A CORPORATION OF MICHIGAN.

PRESSURE-FLUIBQIERATED TOOL.

l Application filed February l, 1926. Serial No. 85,115.

More particularly the invention relates to a pressure fluid operated tool embodying a i'eciproratingv piston and a slidahle sleeve valve, such as, lor example, a pi'ieuinatic rivetiiugv hammer, it being the general object olf the invention to provide new and useiul improvements in a tool of this type whereby the elliciency and effectiveness ol:l the tool are increased.

il. further object'ot the invention is to provide in a tool of this type, improved means whereby the pressure fluid ini-Ly act to sluit the valve quickly and to elli'ectively` retain the valve in itsshitted position.

ln pursuance of the foregoing objects, l aim to provide in a pressure iluid operated tool embodying;- a reciprocating` piston, a sliding `valve adapted to control the inlet and exhaust ot pressure fluid to reciprocate said piston, a chamber adjacent a `flange en said valve, a passage thereto` controlled hy the piston, and means including` an inlet passage adapted to admit pressure fluid to vacunmize said chamber, to retain the valve in one position, the pressure fluid admitted through said inlet passage acting` against said liangi'e to shift said valve when the piston-controlled passage is closed.

Further objects and advantages of the intention will he understood 'from the lollowing` detailed description taken in connecw tion with the accompanying drawings, in which:` i

Figure l .is aview partly in central long gin tudinal section oli a tool cn'ibodying one form of the invention, wherein thevalve is shown in :its orwardposition.

F 2 is a ragmental central longitudinal section in a plane `atan angle to that of Fig. l, wherein the valve is shown in its rear position. The view is somewhat dia- `rrannnatic in that the passage to the torfward end ot the piston chamber is shown in a plane different from thatot Fig. 1 tor the salie ot clearness;

For purposes of disclosure, I have illustrated :in the drawings and will hereinafter describe in detail the preferred embodiment of the invention with the understandin,gr that .l do not intend to limit the invention to the particular construction and arrangement shown, it being contemplated that various changesmay he made by those skilled, in the art without departing 'from the spirit and scope ot' the appended.,claims.

Referring 'to the drawings, the invention inthe exemplary form is shown as emhod'cd in a riveting' hammer comprising;- a harrel l iforlninga piston chamber 2, a` piston 3 mounted for reci])rocatimi therein, a tool 4lsuitably mounted in the barrel at the forward end of the piston chamber and retained thereinhy a customary clip 5and a handle Gsec'lflred to the rear end of the barrel by means of the screw threads 7.

Adjacent the handle end the barrel l. is preferably connterbored to admit a cylin lrical valve casing 8, said casing; being; sccurcd in the vbarrel between the shoulder loii'med at the bottom of the counterhore, and

the handle G. lVithin thisI casing 8 a tuhular valve 9 having an internal here correspending` to that of the piston chamhcr 2, is slidahly mounted.

A supply passage l() in the handle 6 leads to an annular supply chamber 11 termed hetween the rear end of the barrel l, the valve casing-'8 and the handle. From this supply/chamber a plurality oil' passages l2 lead to an annular recess 13 in the piston chainl her to provide an inlet passage to the rear end thereo'l. ln `addition to this inlet passage to the rear end ol the piston chamber, an inlet passage is provided lto the forward. end olf the piston chamber, which passages` together with exhaust passages from the :torward and rear end. oit the piston chamber are adaikiited to he controlled by the slide valve 9.

In the preferred `torni the valve 9 is provided with annular flanges la and l5 and an annular groove 16, the flanges respecs tively engaging-1; annular ,grooves` 17 and `18 in the valve casing,- 8. In addition to these grooves the said `valve casing' is provided with annular ports 19 and 2O and an annular recess 2l, the port 20 being; in constant comlnunication with the atmosphere through an exhaust port 22 in thefvalve casingf tl and harrel l, and the port 19, being in. communication. wlith the forward end of the piston chamber 2 through a passagcl formed also in the said valve casing andbarrel. rlhie valve casing` 8 is iurther provided with an exhaust passage .25 leading from the rear portion oit the groove 1S to the exhaust port 29., and an inlet passage 2.6 leading trom one V,of the passages 12 to a port 26L in the'casing which communicates with the groove 16 in the valve 9 when the valve is 1n its rear position.V The inlet passage 26 1s also connected 'with the groove 18 by a port 26b leading to the rforward portion of said groove. This portis lclosed bythe valve in its forward position`v as shown in Fig. 1 but is uncovered by Vthevalve in the initial portion of its rearward movement. A valve control passage 27 in the valve casing and barrel estab- Alishes communication between the forward portion'of the groove 18 and a port 28 in and intermediate the lends of the piston chamber 2. A portV 24 connects the recess 21 with said passage 27.

Adjacent the rear end of the piston chamber 2 connecting passages 29 and 30 are provided in the valveeasing 8, the passage 29 leading to a rear valve chamber 81 formed between' thevalve'flange 14 and thecasing Y groove 17, and the passage 8O communicating with the piston chamber 2 to the rear of the valve 9'/ Aninlet port 32 in the valve casing 8 establishes constant `'communication befluid in the supply passage 19 is admitted to rthe rear endv of the Ypiston chamber 2 through air inlet. passage comprising the annular supply chamber 11, passages 12 and the recess V13 1n the valve casing. The piston 3 4is driven 'forward by the pressure fluid thus 1 admitted, the portion of the piston chamber forward of the piston exhausting through an exhaustv passage comprising the longitudinal 'passage 23, annular groove 19 in the casing 8,

'groove 16 in the valve 9, groove 2O in the casing and exhaust vport 22. During the forward stroke of the piston the valve 9 is held in its forward position by the force exerted against the rear surface of the flange ,14 by the motive fluid entering chamber 31 from the 'piston chamber through the connecting passages 29 and 30. The forward end9 ofthe valveis vented to exhaust through vrecess 21, vand ports 24, 27 and 28 to the piston chamber forward of the piston so i Vthat leakage from the piston chamber to the forward end of the .valve will not act to move the valverearwardly.

, vAs the piston moves forward it uncovers the port28 inv the piston chamber thereby admitting pressure fluid through the longitudinal control passage 27 tothe groove 18 f yand through port 24to recess 21, vto exert a force'against the flange 15 and against the forward end 9n of the valve 9, to thereby move the valve to its rear position, the force exerted on the flange 15 and said forward end 9n of the valve being greater than that on the rear surface of the flange 14 because of the greater area of the flange 15 and the valve end 9a. Immediately upon the initial movement of the valve rearwardly, line pressure fluid is admitted from passage 26 through the port 26b to the groove 18 to act against the forward surface of the flange lli to assist in the completion of the rau-ward movementl of the valve and in holdingthe valve in its rear position.

The movement of the valve 9 to its rear position cuts oilI the pressure fluid supply to the rear end of the piston chamber by closing the recess 13 and permits exhaustion thereof through the annular port 2O and exhaust port 22. The valve 9 is then held in its rear position by the line pressure fluid admitted to the flange 15 through port 2'6", and also by a suction on the flange 14 caused by the partial vacuum created in the chamber 31 and passage 29 by the jet of motive fluid entering through the inlet passage 82, it' said passage is directed to discharge the fluid across the end of passage 29 into the passage 30 and piston chamber 2.

The port 28 in the piston chamber is so positioned as to correctly time the movement of the valve to its rear position with the impact of the piston on the tool 4 in order that immediately upon the impact, pressure fluid is admitted to the forward end of the piston chamber to return the piston.

As shown in Fig. 2, the valve 9 in its rear position has opened an inlet passage to the forward end of the piston chamber in addi tion to opening the exhaust passage from the rear portion of the piston chamber as hereinbefore described. The inlet passage thus opened comprises the passage 12 in communication with the supply chamber 11, the passage 2G in the valve casing 8, groove 19 in the valve, port 19, and the longitinlinal passage 28 in the valve casing and barrel. The flow of pressure fluid in passage 26 past the port 26" relieves the pressure to some extent in said port and also in groove 18.

The pressure fluid thus admitted is adapted to return the piston, the piston in its return stroke uncovering the port 28 which permits a portion of the motive fluid in the piston chamber forward of the piston to exhaust into the piston chamber to the rear of the piston through the passages 27 and 24. lVhcn upon further movement on the return stroke the piston covers the end of the passage 80, the pressure fluid entering through the port 32 creates a pressure in the chamber 31 which acts upon the rear surface of the flange 14 and moves the valve quickly to its forward position, whereupon pressure lll) fluid is again admitted through the paz-nages l2 andV port 13 to the rear of the piston chamber to drive the piston forward.

It will be apparent that by` 'positioning the port. 30 to `lead into the piston chamber to the rear of the valve a short piston may be used ifV desired. If the port connected `with the piston chamber forward of the valve a short piston mi gllt uncover the port when the piston is in lits extreme rearward posiion and thereby fmale the tool inoperative.

The constantly open inlet passage 32, in conjunction with passages 29 and 30, admits pressurefiuid at practically line pressure to move the valve quickly and positively tc its forward position, and thereby insures a prompt operation of the valve to admit pressure fluid to drive the piston forward. As during the forward stroke of the piston, pressure fluid admitted to the chamber 3l from the piston chamber through passages 30 and 2S), there is practically no movement of air through the restricted inlet 32 but when the rear portion oi the piston chamber is exhausting on the return stroke oi the piston, the inlet passage 32 when positioned as illustrated in the'ipreferred form, dis* Vcharges pressure fluid through passage 30 and effectively retains the valve in its rearward position.

I claim as my invention:

l. A pressure fluid operated tool having, in combination, a barrel forming a piston chamber, a piston mounted for reciprocation in said piston chamber, a tool adapted to be impacted by said piston, a tubular valve slidable within said barrel, said valve having an internal bore corresppnding with that oi the piston chamber and being movable to control the inlet and exhaust of pressure fluid to reciprocate said piston, an annular flange on said valve, means to admit pressure fluid intermittently against said flange to move said valve to its rear position, a second. annular flange surrounding said valve and slid-y ably engaging a groove in said barrel to form a rear valve chamber, an exhaust passage connecting said rear valve chamber with the said piston chamber at a point to the rear of said valve, and a constantly open inlet port leading to said exhaust passage and adapted to direct pressure fluid through said exliaust passage in a direction `to vacuumize said rear valve chamber, said piston, in its reciprocation, closing said exhaust passage whereupon the motive fluid constantly admitted by said inlet port intermittently creates a pressure in said rear valve chamber to shift the valve forward.

2. A pressure fluid operated tool having, in combination, a barrel forming a piston chamber, a piston reciprocable in said chamber, a tubular valve slidable in said barrel and adapted to contre'nl the admission and exhaust of pressure fluid to the said piston chamber to reciprocate said piston, said valve having an external annular flange engaging a groove in said barrel to form a rear valve chamber, and means to operate said valve including an exhaustlpassage connecting said rear valve chamber' with the portion olf the piston chamber to the rearV of said valve,

and an inlet port leading `to said exhaust passage and adapted to direct pressure fluid 'through said exhaust passage in a direction to vacuumize said rear valve chamber.

A pressure fluid operated tool having, in combination, a barrel forming a piston chamber, a piston reciproeable in. said chainber, a tubular valve slidable in said barrel and adapted to control the admission and exhaustof pressure fluid to the said piston chamber to reciprocate said piston, means to reciprocate said valve, and means to retain said valve at one end oli its travel including an external flange on said valve and means to utilize pressure fluid to create a suction on said flange including a constantly open inlet port opening into said piston chamber to the rear of said. valve.

Il. A pressure fluid operated tool having, incombination, a barrel forming a piston chambeiga piston reciprocable in said piston chamber, a tubular valve slidable within said barrel and having an internal bore corresponding with that of the piston chamber, an external fiange on said `valve slidably engaging a groove in said barrel to lQrm a rear valve chamber,` a passage connecting said rear valve chamber with the portion of said piston chamber to the rearolf said valve, and aninlet port leading to said passage adapted constantly to discharge pressure fluid through said passage into the piston chamber, said piston in its reciprocation periodically closing said passage thereby cansv ing the pressure fluid constantly admitted to intermittently exert a pressure :in said valve chamber and against said flange to mo\VH said valve forward.

5. A pressure fluid operated. tool having, in conibination, a barrel forming a piston chamber, a piston reciprocable in said chamber, a valve slidable in said barrel and adapted to control the admission and eX- haust of pressure fluid to the said piston chamber to reciprocate said piston, and means to reciprocate said valve including an external annular flange on said valve engaging a groove in said barrel to :form a valve chamber, an exhaust passage for said valve chamber and a constantly open inlet passage leading to said piston' chamber at the rear of said valve adapted to admit pressure fluid to exhaust said valve chamber through said exhaust passage and to hold the valve in one position, said passage be* ing periodically closed at its discharge eiid by the said piston in its reciprocation to cause v'the pressure fluid admitted by said inlet passage to move'thevalve forward.

. said piston, and means to reciprocate said valve including a rear flange surface on said valve adapted to be acted upon by pressurefluid to move the valve forwardly during `thereturn stroke of the piston, a constantly .open inlet port admitting pressure lluid Vto said-surface, and-an exhaust passage leading to the portion of said piston chamber to the rear of said valve and normy ally open to relieve said pressure on said surface, said exhaust passage being closed by the pistonin its reciprocation.

v7. A pressure'fluid operated tool having, in combination, a barrel forming a piston chamber, a reciprocatory piston, a reciprocatory valve, inlet and exhaust passages to said piston chamber controlled by the opposite ends of said valve, a valve control passage openinginto the mid-portion of said piston chamber adapted to be uncovered by the rearward end of the piston as it travels forwardly, means controlled by the valve in the initial portion of its rearward movement to admit pressure fluid to assist in completing'the rearward movement of the valve, means controlled by the valve operating when vthe valve is in its rearmost position to supply pressure fluid to the forward piston chamber to move the piston rearwardly, .and a port communicating at all times with said control passage and with said exhaust passage when the valve member is in its rearmost position.

8. A pressure fluid operated tool having, in combination, a barrel forming a piston chamber, a reciprocatory piston, a reciprocatory valve adapted to control the inlet and exhaust of pressure fluid to reciprocate said piston, means to reciprocate said valve including a valve control passage governed by said piston and a port uncovered in the initial movement of said valve in one direction to admit pressure fluid to assist in completing the movement of the valve, and means to create a suction to hold the valve in one of its positions including a constantly open inlet port opening into said piston chamber to the rear of said valve.

9. A pressure fluid operated tool having, in combination, a barrel forming a piston chamber, a reciprocatory piston, a reciprocatory valve, inlet and exhaust passages to said piston chamber controlled by the opposite ends of said valve, a valve control passage opening into the mid-portion of said piston chamber adapted to be uncovered by the rearward end of' the piston as it travels forwardly, means controlled by the valve operating when the valve is in its rearniost position to supply pressure to the forward piston chamber to move the piston rearwardly, and a port communicating at all times with said control passage and directly with said piston chamber adjacent the for" ward edge of the valve.

In testimony whereof, I have hereunto aflixed my. signature.

ERNEST H. SHAFF. 

